Dateline: July, 2022, Issue 2

When does juror exposure to negative pre-trial publicity affect deliberations?

Pre-trial publicity (PTP) related to a case often is both sided and slanted, emphasizing primarily negative information in an unbalanced manner about either the defendant or the injured party.

The law takes as a given that voir dire, judicial instruction, and deliberating juror correction are sufficient to de-bias verdicts from any taint from pre-trial publicity. Prospective jurors exposed to PTP routinely are questioned in voir dire about their ability to set aside what they have encountered about the case outside the courtroom. Seated jurors are instructed to base their decision in the case only on the evidence presented during trial. Jurors are expected to correct each other during deliberations should any information beyond the evidence in the case be introduced.

Initial Research

Ruva and Guenther (2017) examined how juries made up of jurors exposed to various types of negative pre-trial publicity differ in their deliberations and decision-making from juries comprised of jurors exposed either to no PTP or only one type of PTP.

Based on an actual criminal case, 648 mock jurors were exposed to one of three types of PTP: negative defendant PTP, negative victim PTP, or irrelevant PTP. The mock jurors exposed to PTP read 6 news stories that were modified from actual PTP surrounding the case, and focused on negative information about the defendant or negative information abuot the victim. Jurors exposed to irrelevant PTP read 6 news stories involving crimes unrelated to the case (e.g., embezzlement, bid rigging, financial fraud, mischief for graffiti).

Approximately one week after the PTP exposure, jurors viewed a trial involving a woman accused of murdering her husband and then deliberated on juries consisting of 4 to 6 jurors. The mock juries were either "pure" (all jurors exposed to the same type of PTP) or "mixed" (half the jurors exposed to one party's negative PTP and the other half exposed to either negative PTP for the other party or to irrelevant PTP).

Jurors provided verdicts three times: as individual jurors after viewing the trial (before deliberations), as a group during jury deliberations, and as individual jurors following jury deliberations.


Pre-trial publicity affected jurors' individual judgments prior to deliberations. Prior to deliberations, jurors exposed to negative defendant PTP were most likely to judge the defendant guilty of murder (68%), while those exposed to negative victim PTP were least likely likely to do so (26%). Jurors exposed to irrelevant PTP were in the middle on judging the defendant guilty of murder (57%).

Exposure to negative pre-trial publicity affected how evidence during the trial was interpreted by jurors. Jurors exposed to negative defendant PTP rated ambiguous and prosecution trial facts as significantly stronger than did jurors exposed either to irrelevant PTP or to negative victim PTP.

During deliberations, "pure" juries rendered verdicts in accord with the bias introduced by the pre-trial publicity. "Pure" negative defendant PTP juries were most likely to render a verdict of guilty (48%), followed by "pure" irrelevant PTP juries (30%), with "pure" negative victim PTP juries (14%) the least likely to find the defendant guilty.

Jurors deliberating on mixed-PTP juries also were influenced by those they deliberated with, and in a disturbing manner. Jurors not exposed to negative PTP incorporated the bias from the negative PTP-exposed jurors on their juries. During deliberations, the bias from negative-PTP jurors spread to jurors not previously exposed to the PTP. Jurors exposed to irrelevant PTP who deliberated with jurors exposed to negative defendant PTP had significantly higher murder guilt ratings after deliberations (5.1 on 7-point scale) than did jurors exposed to irrelevant PTP deliberating on pure irrelevant PTP juries (3.9 on 7-point scale). Said differently, the jurors unexposed to negative defendant PTP picked up the bias of jurors exposed to negative defendant PTP during deliberations.

On mixed juries, unlike bias spread from negative defendant PTP jurors to non-exposed PTP jurors, bias reduction occurred among the jurors exposed to anti-victim PTP, who were more likely on mixed juries to judge the defendant guilty post-deliberations.


Ruva and colleagues (2022) replicated these findings for a shaken baby syndrome case, using 333 jurors and 63 juries. As with the prior research, pure negative victim PTP juries demonstrated a pro-defense bias, and pure negative defendant PTP juries demonstrated a pro-prosecution bias. Mixed juries again evidenced negative defendant PTP bias spread and negative victim PTP bias reduction.

Jury composition was found to have biased the slant of the discussion in deliberations, and this slanted discussion was responsible for the spreading of bias from negative defendant PTP jurors to jurors not exposed to pre-trial publicity.


Pre-trial publicity exposure influences juror decision-making, whether considering individual judgments pre-deliberation, jury verdicts or individual post-deliberation judgments.

Exposure to negative defendant pre-trial publicity results in jurors having an anti-defense bias. Exposure to negative victim pre-trial publicity results in jurors having a pro-defense bias.

When juries are composed both of jurors exposed to negative defendant PTP and those who are not, these mixed juries demonstrate an anti-defendant bias due to bias spread. When mixed juries have members who are exposed to negative victim PTP, the pro-defense bias of these negative victim PTP jurors is attenuated and these jurors vote guilty more often than they would if on a pure jury.

The researchers conclude that, in contrast to the legal assumption that deliberations are effective at correcting and inhibiting bias, deliberations instead provide an opportunity for negative defendant PTP-exposed jurors to spread their bias to jurors not previously exposed to pre-trial publicity.

SourceRuva, C. & Guenther, C.C. (2017). Keep your bias to yourself: How deliberating with differently biased others affects mock-jurors' guilt decisions, perceptions of the defendant, memories, and evidence interpretation. Law and Human Behavior, 41(5), pp. 478-493.

SourceRuva, C.L., Diaz Ortega, S.E., & O'Grady, K.A. (2022). What drives a jury’s deliberation? The influence of pretrial publicity and jury composition on deliberation slant and content. Psychology, Public Policy, and Law, 28(1), pp. 32-52.